The present application is basically for support, for an additional four years, of an ongoing program of vision research by graduate students, postdoctoral fellows and staff at Brown University. Many specific projects will be included, some of which are outlined below. The general plan is to carry out quantitative investigations of visual spatial and temporal resolution. Psychophysical results are compared with the results of electrical recording from the retina and occipital cortex. Human ERG and VECP data are obtained by the use of gross electrodes and signal averaging, and are interpreted through experiments on animal preparations in which electrodes can be used to probe the signals arising from specific cells or regions of the visual system.